Solved Special Triangles (45-45-90 and 30-60-90 ) Worksheet ... - Free Printable
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Step-by-step solution for: Solved Special Triangles (45-45-90 and 30-60-90 ) Worksheet ...
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Step-by-step solution for: Solved Special Triangles (45-45-90 and 30-60-90 ) Worksheet ...
Let's solve each of these special right triangle problems using the properties of 45-45-90 and 30-60-90 triangles.
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1. 45°-45°-90° Triangle
- Legs are equal: $ x $
- Hypotenuse: $ x\sqrt{2} $
2. 30°-60°-90° Triangle
- Side opposite 30°: $ x $
- Side opposite 60°: $ x\sqrt{3} $
- Hypotenuse (opposite 90°): $ 2x $
We'll use these ratios to find missing sides.
---
Given: Hypotenuse = $ 14\sqrt{3} $, angles 45°, 45°, 90°
In a 45-45-90 triangle:
- Hypotenuse = leg × $ \sqrt{2} $
- So: $ \text{leg} = \frac{\text{hypotenuse}}{\sqrt{2}} = \frac{14\sqrt{3}}{\sqrt{2}} $
Simplify:
$$
\frac{14\sqrt{3}}{\sqrt{2}} = 14 \cdot \frac{\sqrt{3}}{\sqrt{2}} = 14 \cdot \frac{\sqrt{6}}{2} = 7\sqrt{6}
$$
So both legs $ p $ and $ q $ are $ 7\sqrt{6} $
✔ $ p = 7\sqrt{6},\quad q = 7\sqrt{6} $
---
Given: Side opposite 30° = $ 6\sqrt{3} $, angle at top is 30°, so that side is shorter leg.
In 30-60-90:
- Short leg (opposite 30°) = $ x $
- Long leg (opposite 60°) = $ x\sqrt{3} $
- Hypotenuse = $ 2x $
Here, short leg = $ 6\sqrt{3} $ → So $ x = 6\sqrt{3} $
Then:
- Hypotenuse $ z = 2x = 2(6\sqrt{3}) = 12\sqrt{3} $
- Long leg $ y = x\sqrt{3} = 6\sqrt{3} \cdot \sqrt{3} = 6 \cdot 3 = 18 $
✔ $ z = 12\sqrt{3},\quad y = 18 $
---
Given: Side opposite 60° = $ \sqrt{5} $, angle at top is 60° → this is the long leg.
In 30-60-90:
- Long leg = $ x\sqrt{3} $
- So $ x\sqrt{3} = \sqrt{5} $ → $ x = \frac{\sqrt{5}}{\sqrt{3}} = \frac{\sqrt{15}}{3} $
Now:
- Short leg $ u $ (opposite 30°) = $ x = \frac{\sqrt{15}}{3} $
- Hypotenuse $ v = 2x = 2 \cdot \frac{\sqrt{15}}{3} = \frac{2\sqrt{15}}{3} $
✔ $ u = \frac{\sqrt{15}}{3},\quad v = \frac{2\sqrt{15}}{3} $
---
Given: Hypotenuse = $ \frac{6\sqrt{2}}{5} $
Use: hypotenuse = leg × $ \sqrt{2} $
So:
$$
\text{leg} = \frac{\text{hypotenuse}}{\sqrt{2}} = \frac{6\sqrt{2}/5}{\sqrt{2}} = \frac{6}{5}
$$
So both legs $ r $ and $ s $ are $ \frac{6}{5} $
✔ $ r = \frac{6}{5},\quad s = \frac{6}{5} $
---
Given: Hypotenuse = $ \frac{13\sqrt{2}}{2} $
Again:
$$
\text{leg} = \frac{\text{hypotenuse}}{\sqrt{2}} = \frac{13\sqrt{2}/2}{\sqrt{2}} = \frac{13}{2}
$$
So both legs $ a $ and $ b $ are $ \frac{13}{2} $
✔ $ a = \frac{13}{2},\quad b = \frac{13}{2} $
---
Given: Side opposite 30° = 16 → this is the short leg = $ x $
So:
- Hypotenuse $ g = 2x = 32 $
- Long leg $ h = x\sqrt{3} = 16\sqrt{3} $
✔ $ g = 32,\quad h = 16\sqrt{3} $
---
Given: Hypotenuse = 18
In 30-60-90:
- Hypotenuse = $ 2x $
- So $ 2x = 18 $ → $ x = 9 $
Then:
- Short leg (opposite 30°) = $ x = 9 $ → this is $ k $
- Long leg (opposite 60°) = $ x\sqrt{3} = 9\sqrt{3} $ → this is $ j $
✔ $ j = 9\sqrt{3},\quad k = 9 $
---
Given: Side opposite 60° = 32 → this is the long leg = $ x\sqrt{3} $
So:
- $ x\sqrt{3} = 32 $ → $ x = \frac{32}{\sqrt{3}} = \frac{32\sqrt{3}}{3} $
Then:
- Short leg $ k $ (opposite 30°) = $ x = \frac{32\sqrt{3}}{3} $
- Hypotenuse $ L = 2x = 2 \cdot \frac{32\sqrt{3}}{3} = \frac{64\sqrt{3}}{3} $
✔ $ k = \frac{32\sqrt{3}}{3},\quad L = \frac{64\sqrt{3}}{3} $
---
| Problem | Answer |
|--------|--------|
| 1 | $ p = 7\sqrt{6},\quad q = 7\sqrt{6} $ |
| 2 | $ z = 12\sqrt{3},\quad y = 18 $ |
| 3 | $ u = \frac{\sqrt{15}}{3},\quad v = \frac{2\sqrt{15}}{3} $ |
| 4 | $ r = \frac{6}{5},\quad s = \frac{6}{5} $ |
| 5 | $ a = \frac{13}{2},\quad b = \frac{13}{2} $ |
| 6 | $ g = 32,\quad h = 16\sqrt{3} $ |
| 7 | $ j = 9\sqrt{3},\quad k = 9 $ |
| 8 | $ k = \frac{32\sqrt{3}}{3},\quad L = \frac{64\sqrt{3}}{3} $ |
Let me know if you'd like these boxed or formatted for printing!
---
🔷 Special Triangle Ratios:
1. 45°-45°-90° Triangle
- Legs are equal: $ x $
- Hypotenuse: $ x\sqrt{2} $
2. 30°-60°-90° Triangle
- Side opposite 30°: $ x $
- Side opposite 60°: $ x\sqrt{3} $
- Hypotenuse (opposite 90°): $ 2x $
We'll use these ratios to find missing sides.
---
✔ Problem 1: 45°-45°-90°
Given: Hypotenuse = $ 14\sqrt{3} $, angles 45°, 45°, 90°
In a 45-45-90 triangle:
- Hypotenuse = leg × $ \sqrt{2} $
- So: $ \text{leg} = \frac{\text{hypotenuse}}{\sqrt{2}} = \frac{14\sqrt{3}}{\sqrt{2}} $
Simplify:
$$
\frac{14\sqrt{3}}{\sqrt{2}} = 14 \cdot \frac{\sqrt{3}}{\sqrt{2}} = 14 \cdot \frac{\sqrt{6}}{2} = 7\sqrt{6}
$$
So both legs $ p $ and $ q $ are $ 7\sqrt{6} $
✔ $ p = 7\sqrt{6},\quad q = 7\sqrt{6} $
---
✔ Problem 2: 30°-60°-90°
Given: Side opposite 30° = $ 6\sqrt{3} $, angle at top is 30°, so that side is shorter leg.
In 30-60-90:
- Short leg (opposite 30°) = $ x $
- Long leg (opposite 60°) = $ x\sqrt{3} $
- Hypotenuse = $ 2x $
Here, short leg = $ 6\sqrt{3} $ → So $ x = 6\sqrt{3} $
Then:
- Hypotenuse $ z = 2x = 2(6\sqrt{3}) = 12\sqrt{3} $
- Long leg $ y = x\sqrt{3} = 6\sqrt{3} \cdot \sqrt{3} = 6 \cdot 3 = 18 $
✔ $ z = 12\sqrt{3},\quad y = 18 $
---
✔ Problem 3: 30°-60°-90°
Given: Side opposite 60° = $ \sqrt{5} $, angle at top is 60° → this is the long leg.
In 30-60-90:
- Long leg = $ x\sqrt{3} $
- So $ x\sqrt{3} = \sqrt{5} $ → $ x = \frac{\sqrt{5}}{\sqrt{3}} = \frac{\sqrt{15}}{3} $
Now:
- Short leg $ u $ (opposite 30°) = $ x = \frac{\sqrt{15}}{3} $
- Hypotenuse $ v = 2x = 2 \cdot \frac{\sqrt{15}}{3} = \frac{2\sqrt{15}}{3} $
✔ $ u = \frac{\sqrt{15}}{3},\quad v = \frac{2\sqrt{15}}{3} $
---
✔ Problem 4: 45°-45°-90°
Given: Hypotenuse = $ \frac{6\sqrt{2}}{5} $
Use: hypotenuse = leg × $ \sqrt{2} $
So:
$$
\text{leg} = \frac{\text{hypotenuse}}{\sqrt{2}} = \frac{6\sqrt{2}/5}{\sqrt{2}} = \frac{6}{5}
$$
So both legs $ r $ and $ s $ are $ \frac{6}{5} $
✔ $ r = \frac{6}{5},\quad s = \frac{6}{5} $
---
✔ Problem 5: 45°-45°-90°
Given: Hypotenuse = $ \frac{13\sqrt{2}}{2} $
Again:
$$
\text{leg} = \frac{\text{hypotenuse}}{\sqrt{2}} = \frac{13\sqrt{2}/2}{\sqrt{2}} = \frac{13}{2}
$$
So both legs $ a $ and $ b $ are $ \frac{13}{2} $
✔ $ a = \frac{13}{2},\quad b = \frac{13}{2} $
---
✔ Problem 6: 30°-60°-90°
Given: Side opposite 30° = 16 → this is the short leg = $ x $
So:
- Hypotenuse $ g = 2x = 32 $
- Long leg $ h = x\sqrt{3} = 16\sqrt{3} $
✔ $ g = 32,\quad h = 16\sqrt{3} $
---
✔ Problem 7: 30°-60°-90°
Given: Hypotenuse = 18
In 30-60-90:
- Hypotenuse = $ 2x $
- So $ 2x = 18 $ → $ x = 9 $
Then:
- Short leg (opposite 30°) = $ x = 9 $ → this is $ k $
- Long leg (opposite 60°) = $ x\sqrt{3} = 9\sqrt{3} $ → this is $ j $
✔ $ j = 9\sqrt{3},\quad k = 9 $
---
✔ Problem 8: 30°-60°-90°
Given: Side opposite 60° = 32 → this is the long leg = $ x\sqrt{3} $
So:
- $ x\sqrt{3} = 32 $ → $ x = \frac{32}{\sqrt{3}} = \frac{32\sqrt{3}}{3} $
Then:
- Short leg $ k $ (opposite 30°) = $ x = \frac{32\sqrt{3}}{3} $
- Hypotenuse $ L = 2x = 2 \cdot \frac{32\sqrt{3}}{3} = \frac{64\sqrt{3}}{3} $
✔ $ k = \frac{32\sqrt{3}}{3},\quad L = \frac{64\sqrt{3}}{3} $
---
✔ Final Answers:
| Problem | Answer |
|--------|--------|
| 1 | $ p = 7\sqrt{6},\quad q = 7\sqrt{6} $ |
| 2 | $ z = 12\sqrt{3},\quad y = 18 $ |
| 3 | $ u = \frac{\sqrt{15}}{3},\quad v = \frac{2\sqrt{15}}{3} $ |
| 4 | $ r = \frac{6}{5},\quad s = \frac{6}{5} $ |
| 5 | $ a = \frac{13}{2},\quad b = \frac{13}{2} $ |
| 6 | $ g = 32,\quad h = 16\sqrt{3} $ |
| 7 | $ j = 9\sqrt{3},\quad k = 9 $ |
| 8 | $ k = \frac{32\sqrt{3}}{3},\quad L = \frac{64\sqrt{3}}{3} $ |
Let me know if you'd like these boxed or formatted for printing!
Parent Tip: Review the logic above to help your child master the concept of 30 60 90 triangle worksheet.